Apparatus for purifying metals



G. H. SITTNER APPARATUS FOR PURIFYING METALS (ANH )PH April 24, 1951 2 Sheets-Sheet 1 Filed Jan. 30, 1948 T-wenlov George H. Sibbner, be

His Attorney.

April 24, 19.51 A G; lH, SITTNER 2,550,502 I APPARATUS FOR PURIFYING METALS Filed Jan. 50, 1948 2 Sheets-Sheet 2 Fig a,

hvenov". C-eorgwI H. Sibbrler,

by His Attorney.

Patented Apr. 24, 1951 APPARATUS FOR PURIFYING METALS George H. Sittner, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application January 30, 1948, Serial No. 5,346

(Cl. 26S-37) 2 Claims.

My invention relates to apparatus for melting and purifying metals. More particularly the invention deals with apparatus for the melting and separation of impurities from lead while in the molten state.

In the manufacture of electric cables, molten lead is fed from a lead melting pot to the cylinder of a lead press and is extruded therefrom onto the insulated cable to serve as a lead sheath which is impervious and prevents the admission of air or water to the `cable or the loss of insulating oils. The lead melting pots now in use do not supply lead to the lead cylinder free from deleterious admixtures such as slag inclusions, oxides and other impurities. Nevertheless, it has long been a desire of the cable manufacturing industry to obtain a pot which would perform this operation as it has been found that cables covered by pure lead are far superior in service to those sheathed in lead containing impurities.

It is, therefore, an'object of my invention to provide a novel apparatus for melting and sepa- Y rating or cleaning impurities from molten lead vide apparatus for the separation of solid imf purities from molten lead and permit simultaneous or separate discharge of purified molten lead and the impurities from the apparatus.

In accordance with my invention I rotate a molten mass of lead or metal containing solid impurities to centrifugally force the heavier and purified portion of the mass from the lighter impurities which I discharge from the surface and center ofthe rotating mass while the purified portion is discharged from the periphery there- Yof.

My invention will be better understood from`l the following description when taken in connection with the accompanying drawings and the scope of my invention will be pointed out in the appended claims. In the drawing, Fig. 1 is an elevation View. partly in section, of a metal melting and cleaning apparatus of my invention illustrating purified metal being discharged therefrom; Fig. 2 is a top plan-view of the apparatus shown in Fig. l; Fig. 3 is a section taken on the line 3-3 of Fig. l.; Fig. 4 is an enlarged partial section taken on theline I--il of Fig. 2; Fig. 5 is an elevation View partly in section illustrating a modification of my invention; Fig. V6 is a top plan view partly in section of the apparatus shown by Fig. 5, Fig. I is an elevation view partly in section illustrating still another modification of my invention, and Fig. 8 is a top plan View of the Fig. '7 modification.

Referring now to Figures 1, 2, 3 and 4 of the drawings, I have shown a cone-shaped melting pot or chamber I having an annular ange 2 projecting outwardly from the top edge thereof by which the weight of the pot is transmitted by columns, not shown, to a supporting structure 3. Another cone-shaped pot or chamber 4, which I call a centrifugal chamber and which also has an annular flange 5 is mounted concentrically within the melting pot I and the interior of the chamber is interconnected with the interior of pot I by apertures or openings 5 in the Wall of the centrifugal pot adjacent its base. The annular space between the two pots is partially divided into two concentric annular spaces l and 8 by a cone-shaped baille 9 integral with and projecting downwardly from an annular ring 9 mounted by means of lugs III, integral therewith, on flange 2. The lugs II) are bolted to flange 2 and 5 the ring 9' is bolted to flange 5 of centrifugal pct 4 with a gasket, not shown, therebetween so that the inner annular space 8 is sealingly covered while the outer annular space I is partially uncovered, as indicated by the numeral II, between the supporting lugs I 0. Centrifugal chamber 4 is provided with an opening I2 in the wall thereof adjacent the top which is aligned with a passage I3 interconnecting opening I2 with an opening I4 in the wall of melting chamber I. A

pipe I5 leading to the lead press, not shown, is aligned with passage I3 and sealingly connected to the chamber I. A valve I6, operable from the exterior of the apparatus, serves to close off the passage I3 if so desired. A tube I1 is axially mounted within thev centrifugal chamber 4 and passes to the exterior through the base thereof and the base of chamber I. The tube I'I is so positioned that the open end thereof within the centrifugal chamber is at, an elevation above the bottom of opening I2 in the wall of thechamber. A rotor or agitator comprising four blades or paddles I8 is mounted for rotation within centrifugal chamber 4 and about axial tube I'I. The

Vlower ends of blades I8 are interconnected and fugal chamber 4, through' drive tube 23 and' bevel gear 24 affixed thereto. Bevel gear 25 meshing with gear 24mounted on the same shaftdischarged metal can be continuously made up without shutting down the operation by the continual addition of pig lead to melting pot 52.

Thus far my invention has been described in connection with apparatus in which a mechanical agitator is employed to rotate a molten mass of metal and thereby separate the impurities from pure metal by centrifugal force and in which puried molten metal is discharged from the periphery and the surface of the mass. However, it should be apparent that the employment of other means for rotating a mass of molten metal is clearly within the scope of my invention. Moreover, practice of my invention is not contingent upon the employment of a separate melting chamber vnor the discharge of metal from the surface of a rotating mass within a centrifugal chamber since purified metal will always be concentrated at any point of the periphery of the rotating mass.

Thus in Fig. 5 I have illustrated another modification which comprises a combined centrifugal and melting chamber 55, an axially positioned impurities drain tube 56 with Valve 51 to close off the open end thereof, a purified metal discharge opening 58 withvalve 59 operable from the exterior by means of extension rod 60 and a cover 6l supported by supporting lugs 62 on the top flange of chamber 55. Pig metal, introducedl into the chamber through openings 63 between lugs 62 is melted by electric heating elements 64 or other heating means, and the mass of molten metal is rotated by means of jets of inert gas ejected from a plurality of nozzles or openings 65 tangentially positioned in the wall of the chamber. The gas is fed to each nozzle through risers 66 from header 61 and feed pipe 68 in which is a control valve, not shown. When it is desired to discharge impurities which have collected at the surface and center of the mass the gas pressure to the nozzles is raised or lowered, as the case may be, to respectively either increase the speed of rotation of the mass and thus lower the surface level at the center, or decrease the speed of rotation and thereby raise the surface at the center. In either case, when the center of the surface is at or slightly above the end of discharge or drain tube 56 as indicated by broken line 69, valve 51 is raised and the impurities are allowed to drain down tube 56 and out of the apparatus. It is to be noted that in this modification various speeds of rotation of the mass are employed to control only the discharge of impurities since the purified metal may be drawn off by gravity from the periphery of the rotating mass, through opening 58 adjacent the base of the pot 55. Obviously this opening may be 1ocated at any point in the wall of the pot.

While I have, in accordance with the patent statutes, shown and described a particular embodiment of my invention and modifications thereof, other changes and modifications will be obvious to those skilled in the art and I, therefore, aim in the appended claims to cover all 'such changes and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a lead melting and cleaning apparatus a melting and pressure chamber, a centrifugal chamber having adischarge opening adjacent the top in the wall thereof with a valve therein controlling the flow of molten lead through said opening and another opening in the wall of said centrifugal chamber adjacent the base thereof interconnecting said chamber with said melting and pressure chamber, a rotatable agitator within said centrifugal chamber with the axis of rotation thereof coincident with the axis of said chamber, an impurities drain tube axially disposed within said centrifugal chamber, an end of said tube within said chamber located at an elevation above said discharge opening in the wall of said chamber, and heating means mounted in heat exchange relationship to said chambers to melt and maintain the lead in said 'chambers in a molten state.

2. In an apparatus for melting and cleaning a mass of molten metal by centrifugal action, a cone-shaped melting chamber, a cone-shaped centrifugal chamber concentrically disposed within and spaced from said melting chamber, a covering means partially enclosing the annular space between said chambers, a cone-shaped baffle projecting into said annular space from said covering means so that a portion of said annular space is divided into two separate and concentric annular spaces, the inner one of which is completely and sealingly covered, a pipe connection opening in said cover enclosing said inner space, said centrifugal chamber having an opening in the wall and adjacent the base thereof interconnecting said chamber with said melting chamber, a molten metal discharge openingadjacent the top in the wall of said centrifugal chamber and a valve in said opening for controlling the flow of molten metal therethrough, an impurities drain tube axially disposed within said chamber and passing exteriorly through the base thereof, the end of said tube within said chamber located at an elevation above said molten metal discharge opening in the wall of said chamber, a valve controlling the flow of impurities through said tubes, a mechanical agitator axially mounted for rotation within said chambe` and about said tube, a cylindrical baille mounted on the upper portion of said agitator and projecting downwardly to a point below the location of said molten metal discharge opening, a cover' enclosing the top of said centrifugal chamber with a pipe connection opening and an axially disposed opening therein for interconnecting said agitator with an external driving means and for operating said discharge tube valve from the exterior, and heating means mounted in heat exchange relationship to said chambers to melt and maintain the metal in said chambers in a molten state.

GEORGE I-I. SITTNER.

REFERENCES CITED f The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 4566,921 Mays Sept. 1, 1896 1,101,548 I-Ioifman June 30, 1914 1,301,544 Crombie Apr. 22, 1919 2,025,768 Nieman Dec. 31, 1935 2,099,593 Bender Nov. 16, 1937 2,241,806 Burkey May 13, 1941 2,335,569 Monson et al Nov. 30, 1943 2,404,364 Cooper et al. July 28, 1946 

